Screwy Electrical Panels

So, if your house has one, you’ve likely got a problem…maybe not today, but soon, and for the rest of its life.

Screw fuses were neat little devices, in their time. The fuses have a metal bit inside that burns up if too much current passes through. It’s similar to what happens when an incandescent light bulb burns out, except the fuse does it on purpose.

Once the fuse pops, you have to unscrew it from the panel and screw in a new one (this was quite a trick, in the dark, after one had popped). The problem comes in that, when you unscrew the fuse, the wiring is exposed. The fuse popping means that the extra current isn’t flowing into your house, but the incoming wire is still ‘hot’ (it still has electricity flowing to it). Touch the wrong thing while replacing the fuse, or put the fuse in wrong, and you’ll be in for a shocking surprise. (Additionally, and admittedly more of an irritation than a safety problem, once the fuse popped, it’s trash; you have to keep spares around. Forget to pick up spares when you run out, and you risk having a very dark night. The switch-flip breakers on more current equipment are a vast improvement.)

This is the casing for the tube fuses. The screw fuses (at least, the small standard ones like above) are only rated for 120 volt circuits. The tubes are for the 240V circuits, like your stove or dryer or HVAC. They’ve got the same problem as the screw fuses, they’re just harder to put in and pull out. In the picture, each metal handle is for one tube. If you don’t have big fingers, you might be able to get two fingers into the handle, then yank out. They tend to stick in place, as the connection points have to be relatively large to handle the current. (On the up side, the 240V circuits don’t tend to control the lights, so if you have to replace one, it’s unlikely to be in the dark. Small victories…)

I do come across these types of old panels from time to time. Certain areas around here have a lot of 1930’s/1940’s construction, and depending on how and when things got renovated, sometimes the old panels never got replaced (often times, it’s a ‘if it ain’t broke, don’t fix it’ scenario). However, they are obsolete, and potentially dangerous. The new styles of fuses are vastly superior, especially when you start looking at GFI and Arc-Fault breakers.

If you find one of these in your potential new home, be aware that the general ballpark replacement cost is around $2000, and you should really should have it taken care of sooner rather than later. They are a really interesting piece of history, but I do hope your house doesn’t have one.